Heart rate monitors are popular among athletes but more and more people at all fitness levels are starting to use them as an additional and important tool to monitor their health and the impact of their exercise schedule on their well being. Manufacturers of such heart rate monitors offer various models having differing configurations and functions, many designed and marketed for specific sporting activities such as running, cycling, etc.
A typical hear rate monitor consists of a watch worn on the user's wrist, and a heart rate detector that is worn against the user's skin around the chest. The detector is often embodied in a belt that may be adjusted to fit comfortably around the user's chest. The detector includes electrocardiogram (EKG) electrodes that are able to detect the electrical signals from the user's heart. These signals are then wirelessly transmitted to the watch worn on the user's wrist by a transmitter included in the detector. This watch typically includes a processor that converts these signals into a heart rate number and a display on which the heart rate number is displayed, preferably continuously. One such hear rate is described in U.S. Pat. No. 6,282,439, entitled Method of Measuring Vital Function and Measuring Device, assigned to Polar Electro Oy.
While current heart rate monitors are used by and marketed to athletes to provide them with information regarding their intensity of exercise or exertion level so that the athletes can train and compete at an optimum level, such heart rate monitors do little more than display a heart rate number for the user to look at. Some more complex heart rate monitors can also measure altitude and ascent, and can associate the monitored heart rate with this information to provide the user with a graphic illustration of this information so that the user can, later, review how his or her heart rate varied during the various periods of exertion during the training session. While this information is informative to the user and while the user can review this information to see if his or her overall level of fitness appears to be improving (e.g. by observing a sustained pace with a heart rate that is lower than previously observed by the user at the same pace), the heart rate monitor does not actually utilize this information for any health related calculations. Some heart rate monitors do provide an alarm that sounds when the monitored heart rate exceeds a user set maximum heart rate. However, this alarm is again merely informational and is not adjusted or varied when other parameters change, such as altitude, even though the level of exertion and effect on the body may well be affected by such other parameters.
One such sporting activity in which careful monitoring of exertion level changes are critically important is scuba diving, since inert gas uptake and elimination (which can lead to decompression sickness) are strongly affected by blood circulation. While many scuba divers wear a dive computer during a dive to monitor dive time, depth, etc. and to calculate appropriate decompression stops during ascent, etc., currently there are no dive computers that include a heart rate monitor.
There exists, therefore, a need in the art for a diving computer that includes a heart rate monitor that not only monitors and displays heart rate information, but that can utilize this monitored heart rate information in calculations towards diver safety. The invention provides such a dive computer. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.